1. Field of the Invention
This invention relates to a multipulse starting aid for high intensity discharge lamps. Accordingly, it is a general object of this invention to provide new and improved aids and generators of such character.
2. General Background
U.S. Pat. No. 4,325,004, issured Apr. 13, 1982, "Method and Aapparatus for Starting High Intensity Discharge Lamps", Joseph M. Proud, Leslie A. Riseberg, and Charels N. Fallier, Jr.; U.S. Pat. No. 4,353,012, issued Oct. 5, 1982, "Pulse Injection Starting For High Intensity Discharge Metal Halide Lamps", Charles N. Fallier, Jr. and Joseph M. Proud; and U.S. Pat. No. 4,484,085, issued Nov. 20, 1984, "Spiral Line Voltage Pulse Generator Characterized by Secondary Winding", Charles N. Fallier Jr. and Joseph M. Proud, teach the use of spiral line generators for triggering high-intensity discharge lamps. Spiral line pulse generators are described in U.S. Pat. No. 3,289,015 and in "Novel Principle of Transient High Voltage Generator" by Fitch et al., Proceedings IEEE, Vol 111, No. 4, April (1964).
High-intensity discharge lamps, in the prior art, were normally triggered by a single high voltage pulse at the peak of an open circuit ballast waveform. Disadvantageously, however, a single high voltage pulse, typically one microsecond wide, would, in some cases, not be sufficient to initiate a glow discharge to start a high intensity discharge lamp.